Scalable Manufacturing of Nanogaps

Abstract

The ability to manufacture a nanogap in between two electrodes has proven a powerful catalyst for scientific discoveries in nanoscience and molecular electronics. A wide range of bottom-up and top-down methodologies are now available to fabricate nanogaps that are less than 10 nm wide. However, most available techniques involve time-consuming serial processes that are not compatible with large-scale manufacturing of nanogap devices. The scalable manufacturing of sub-10 nm gaps remains a great technological challenge that currently hinders both experimental nanoscience and the prospects for commercial exploitation of nanogap devices. Here, available nanogap fabrication methodologies are reviewed and a detailed comparison of their merits is provided, with special focus on large-scale and reproducible manufacturing of nanogaps. The most promising approaches that could achieve a breakthrough in research and commercial applications are identified. Emerging scalable nanogap manufacturing methodologies will ultimately enable applications with high scientific and societal impact, including high-speed whole genome sequencing, electromechanical computing, and molecular electronics using nanogap electrodes.

Sub‐5 nm Metal Nanogaps: Physical Properties, Fabrication Methods, and Device Applications

“…Previously, metal nanogaps have been reviewed with different specific focuses, such as on fabrication methods based on physical [39] or chemical methods, [40] various applications in specific areas, including electrodes, [41,42] molecular devices, [43,44] Compared with the relatively mature fabrication methods for nanogaps, sub-5 nm is a critical gap size that requires special methods to achieve. Moreover, many important properties and applications can only be achieved with sub-5 nm nanogaps, and the corresponding fabrication and devices are more challenging; thus, this area deserves more attention.…”

“…Previously, metal nanogaps have been reviewed with different specific focuses, such as on fabrication methods based on physical or chemical methods, various applications in specific areas, including electrodes, molecular devices, or plasmonic devices, and fabrication techniques for massive production . These reviews offer very good references for researchers and practitioners from a very specific perspective or from a broad view of metal nanogaps.…”

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www.small-journal.com plasmonic devices, [40,45] and fabrication techniques for massive production. [39,40] These reviews offer very good references for researchers and practitioners from a very specific perspective or from a broad view of metal nanogaps. The sizes of the nanogaps reported in these reviews are wide, ranging from subnanometer to tens of nanometers, without a specific selection.

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Scaling Organic Electrochemical Transistors Down to Nanosized Channels

“…The typical fees to pay are related to device heating issues, standard photolithography resolution limits, process compatibility, and process optimization with respect to all the possible critical steps. Nanogap technology is a top‐down approach to nanopatterning, which is particularly suited to obtain electrodes with nanometric distance and hence to define a nanosized channel for the fabrication of molecular biosensors allowing the detection of single‐molecules as, for example, single nucleotides.…”

“…[1] Poly(3,4-ethylenedioxythiophene) polystyrene steps. Nanogap technology [19] is a top-down approach to nanopatterning, which is particularly suited to obtain electrodes with nanometric distance and hence to define a nanosized channel for the fabrication of molecular biosensors allowing the detection of single-molecules as, for example, single nucleotides.…”